Triphenylene as a versatile scaffold for advanced functional materials.

Triphenylenes are a class of polycyclic aromatic hydrocarbon that have been attracting increasing attention owing to their widespread applications in areas such as liquid crystals, organic electronics, photovoltaics, light emitting diodes, and catalysts. The utility of triphenylenes stems from their flatness, rigidity, and aromatic nature. This review provides an exploration of triphenylene derivatives, with an emphasis on recent advancements in their synthesis, properties, and multifaceted applications. Highlighting their synthetic strategies, we discuss both classical methods and modern approaches, including metal-catalyzed reactions and photochemical techniques, which have enabled the development of a wide range of substituted triphenylenes, as well as their dimers, trimers, twinned molecules, and oligomers. The electronic structure of triphenylene, characterized by a delocalized π-electron system, underpins its remarkable charge transport properties. In terms of applications, triphenylene-based liquid crystals are particularly notable for forming columnar mesophases with highly ordered structures, facilitating advantageous macroscopic molecular orientation. These properties underscore its potential for next-generation functional materials across diverse domains, including organic electronics, photovoltaics, light-emitting diodes, and catalysis. By integrating insights into its properties and future potential, this review aims to provide a valuable resource for researchers investigating triphenylene and its derivatives.